Extended range and ultra-precision non-contact dimensional gauge

摘要: A non-contact pneumatic-electric dimensional measurement system comprises a stable base on which semiconductor wafer or workpiece to be measured is placed. head held aloft over the and by rigid support bracket attached base. The tip of an air nozzle in directed at automatically extended near contact. servo-positioned sensor motor combination that maintains gap between about 150 microns with overall precision 3-4 microns. Heidenhaim linear displacement gauge used determine position within 0.5 micron. dimension determined micron combining reading estimate derived from backpressure has accuracy 0.1 calibration method while servo temporarily disabled. stepped ten increments reference starting zero using readings gauge. specific back pressure read into linearization table for 0-300 steps.